﻿// Spun AJAX Framework
// Copyright (C) 2008 Blake Hegerle
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace Spun.Applications
{
    public class TokenManager
    {
        public TokenManager()
        {
            Hasher = new HMACSHA1();
        }

        public void SignToken(Token Token)
        {
            byte[] IdArray = ToArray(Token.Key);

            var Hash = Hasher.ComputeHash(IdArray);

            Token.Hash = Convert.ToBase64String(Hash);
        }

        public bool ValidateToken(Token Token)
        {
            var Hash = Token.Hash;

            if (Hash == null)
                return false;

            SignToken(Token);

            return Hash.Equals(Token.Hash);
        }

        private static byte[] ToArray(ulong Id)
        {
            var Stream = new MemoryStream();
            var Writer = new StreamWriter(Stream);

            Writer.Write(Id);
            Writer.Flush();

            return Stream.ToArray();
        }

        private HashAlgorithm Hasher;
    }
}
